Introduction & History of Computers, Their

Applications

By: Khalid Khan

Sarhad University of Science & Information Technology Peshawar

Contents• What is Computer?• Who is a User?• Data & Information• Information Technology (IT)• History of Computers

• Generations• Types of Computers• Classification of Computers

What is Computer

What is Computer?Definitions:• A computer is normally considered as

calculating machine that can perform arithmetic operation at a very high speed.

• Computers are electronic devices that is programmed to • accept data (input), • (process) that data into useful information, • produce (output), and then • (store) for later use.

Who is a user?• Someone that communicates with a

computer

Data & InformationDefinitions:• DATA A collection of raw facts and figures is called data. It may consist of numbers, characters, symbols

etc

• INFORMATION Processed data is called information. It is more meaningful than data.

Information Technology• Information is data that is organized,

meaningful, and useful.• Information technology is the use of

systems (especially computers and telecommunications) for storing, retrieving, and sending information..

• Computer is a very important component of information technology

History of Computers

Mechanical computers

(1600-1900)early designs for

more traditional computers - based on mechanical techniques.

Slide rule

Abacus

Pascal Calculator

Electronic computers(1937-1953)

First Generation - Vacuum Tubes

1. From 1946 to 1956 •It can perform 2,000 to 16,000 additions per second •Had main memory 100 bytes to 2 kilobytes

2. Used vacuum tubes 3. Very large machines

•special rooms to house them with air conditioning •specially trained technicians to run & maintain

Second Generation - Transistors

1.From 1959 to around 1965 2.Smaller, faster, and more reliable

used transistors 6,000 to 3,00,000 operations/s main memory 6 kilobytes to 1.3

megabytes3.one-tenth the price of a 1st

Generation4.become common in larger

businesses and universities

Third Generation - Integrated Circuits

1. Form 1965 to around 1972 2. Used integrated circuits – many

transistors on one piece of silicon 3. Smaller, faster, more reliable, and

lower in price • Size of a stove or refrigerator, some can fit

on desktops • Can do 100,000 to 400,000,000 operations

per second • Cost about one-tenth the amount of second

generation computers 4. These Computers become very

common in medium to large businesses

Fourth Generation - Microprocessors1. From 1972 until now 2. Used large scale to very large scale integrated

circuits • Put more than one IC on a silicon chip • Can do more than one function

3. smaller, faster, more reliable, and lower in price • Size of a television or much smaller • Can do 500,000 to 1,000,000,000

operations/second • Cost one-tenth, or less, the amount of third

generation 4. very common in homes and business

Types of Computer

• Analog computers

• Digital computers

Analog Computers• An analog computer recognizes data as a

continuous measurement of a physical property.

• It has no state• Its output is usually displayed on a meter

or graphs.• Examples are Analog clock, speedo-meter

of a car, thermo-meter etc

Digital Computers• It works with numbers• They breaks all types of information into tiny

units and use numbers to represent those pieces of information.

• Everything is described in two states i.e. either ON (1) or OFF (0).

• They are very fast and have big memory

Classification of Computers

Basic Map

Micro Computers

Mainframe Computers

Super Computers

Mini Computers

Digital Computers

Desktop Computers

Laptop Computers

Handheld Computers

Workstations Computers

Servers Computers

Supercomputer• A supercomputer is a computer with a high-level

computational capacity compared to a general-purpose computer.

• It comprised of multiple high performance computers working in parallel as a single system.

• Super Computers uses thousands of processor at a same time.

• Used for nuclear weapon weather forecasting, Scientific Simulition, oil and gas exploration or in large companies.

Mainframe• Mainframes are huge

computers that could fill an entire room or even a whole floor!

• mainframes can run multiple instances of operating systems at the same time.

•  Mainframe are used primarily by large organizations for critical applications, bulk data processing

• It uses for online data storage.• Mainframe used for

transaction processing in banking, Airlines etc

Workstation• A desktop computer that has a more powerful

processor,

• additional memory (RAM, Hard drive) and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development.

• Multiple users can use single workstation all together.

Server• A computer that has been optimized to provide

services to other computers over a network.

• Servers usually have powerful processors, lots of memory and large hard drives.

• Multiple CPU’s & Hard drives

DESKTOP

• A PC that is not designed for portability.

• you will set the computer up in a permanent location.

• Most desktops offer more power, storage and versatility for less cost than portable computers.

                                                             

Laptop

• Also called notebooks.

• Laptop are portable computers that integrate the display, keyboard, a pointing device or trackball, processor, memory and hard drive all in a battery-operated package.

                                        

Palmtop• More commonly known as Personal

Digital Assistants (PDAs) • palmtops are tightly integrated

computers that often use flash memory instead of a hard drive for storage.

• usually do not have keyboards but rely on touchscreen technology for user input.

• A slightly larger and heavier version of the palmtop is the handheld computer.